Treatment of ocular hypertension with a synergistic combination

ABSTRACT

A method for treatment of ocular hypertension which comprises ocularly administering, to a subject in need of such treatment, an oculo-hypotensively synergistic combination of 
     (a) a 15-ketoprostaglandin or a pharmaceutically acceptable salt thereof, or a pharmaceutically acceptable ester thereof, and 
     (b) a carbonate dehydratase inhibitor in an amount effective in treatment of ocular hypertension.

This is a Continuation of application Ser. No. 08/352,822 filed Dec. 1,1994 now abandoned, in turn a continuation of application Ser. No.08/051,434, Apr. 23, 1993, abandoned, in turn a continuation ofapplication Ser. No. 07/833,025, Feb. 10, 1992, abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a treatment of ocular hypertension witha synergistic combination comprising (a) a 15-ketoprostaglandin compoundand (b) a carbonate dehydratase inhibitor. Said combination ischaracterized by an improved effect and a reduced side-effect.

The compounds used as the component (a) in the present invention areprostaglandin analogues which can be obtained synthetically.

2. Information of Prior Art

Prostaglandins (hereinafter, prostaglandins are referred to as PGs) aremembers of a class of organic carboxylic acid that are contained inhuman and most other mammalian tissues or organs and that exhibit a widerange of physiological activities. Naturally occurring PGs possess as acommon structural feature the prostanoic acid skeleton: ##STR1## Somesynthetic analogues have somewhat modified skeletons. The primary PGsare classified based on the structural feature of the five-memberedcycle moiety into PGAs, PGBs, PGCs, PGDs, PGEs, PGFs, PGGs, PGHs, PGIsand PGJs, and also on the presence or absence of unsaturation andoxidation in the chain moiety as:

    ______________________________________                                        Subscript 1    13,14-unsaturated-15-OH                                        Subscript 2    5,6- and 13,14-diunsaturated-                                                 15-OH                                                          Subscript 3    5,6- 13,14- and 17,18-                                                        triunsaturated-15-OH                                           ______________________________________                                    

Further, PGFs are sub-classified according to the configuration ofhydroxy group at position 9 into α(hydroxy group being in the alphaconfiguration) and β(hydroxy group being in the beta configuration).

The fact that the above compounds under item (a) have ocular hypotensiveactivity has been known by Japanese Patent Publication No. A-108/1990and No. A-96528/1990. The carbonate dehydratase inhibitor referred tounder item (b) refers to the agents capable of specifically inhibitingenzymes which take part in the reversible reaction forming carbonatefrom carbon dioxide and water in living organisms, and is known to havepharmacological activities such as ocular hypotension. It has also beendescribed in Japanese Patent Publication A-313728/1988 thatprostaglandins can be coadministered with an adrenergic blocker. Suchdescription, however, neither show a combined use of the carbonatedehydratase inhibitor and the component (a) in the present invention norsuggest that said combined use may cause synergistic increase in effector decrease in side-effect because the adrenergic blockers are agentswhich inhibit the binding of the adrenergic agents with the adrenergicreceptors thus exerting their pharmacological activity.

After an extensive study on the possibility that the effect of thecomponent. (a) in the present invention is improved by combining it witha variety of compounds, the present inventor has surprisingly discoveredthat the effect of the component (a) is significantly improved andside-effect is decreased by co-administration with a carbonatedehydratase inhibitor such as acetazolamide. Said discovery leads to thepresent invention.

SUMMARY OF THE INVENTION

In a first aspect, the present invention provides a method for treatmentof ocular hypertension which comprises ocularly administering, to asubject in need of such treatment, an oculo-hypotensively synergisticcombination of

(a) a 15-ketoprostaglandin or a pharmaceutically acceptable saltthereof, or a pharmaceutically acceptable ester thereof, and

(b) a carbonate dehydratase inhibitor in an amount effective intreatment of ocular hypertension.

In a second aspect, the present invention provides a use of anoculo-hypotensively synergistic combination of

(a) a 15-ketoprostaglandin or a pharmaceutically acceptable saltthereof, or a pharmaceutically acceptable ester thereof, and

(b) a carbonate dehydratase inhibitor for the manufacture of amedicament useful in treatment of ocular hypertension.

In a third aspect, the present invention provides a pharmaceuticalcomposition for treatment of ocular hypertension which comprising anoculo-hypotensively synergistic combination of

(a) a 15-ketoprostaglandin or a pharmaceutically acceptable saltthereof, or a pharmaceutically acceptable ester thereof, and

(b) a carbonate dehydratase inhibitor in association with apharmaceutically acceptable carrier, diluent or excipient.

DETAILED DESCRIPTION OF THE INVENTION

The "15-ketoprostaglandins", used as the component (a) in the presentinvention and referred to as the component (a), include anyprostaglandin derivatives which have a single bond, a double bond or atriple bond between positions 13 and 14 and an oxo group in place of thehydroxy group at position 15 of the prostanoic acid nucleus.

Nomenclature

Nomenclature of the component (a) herein uses the numbering system ofprostanoic acid represented in formula (A) shown above.

While formula (A) shows a basic skeleton having twenty carbon atoms, the15-keto-PG compounds used in the present invention are not limited tothose having the same number of carbon atoms. The carbon atoms inFormula (A) are numbered 2 to 7 on the α-chain starting from theα-carbon atom adjacent to the carboxylic carbon atom which is numbered 1and towards the five-membered ring, 8 to 12 on the said ring startingfrom the carbon atom on which the α-chain is attached, and 13 to 20 onthe ω-chain starting from the carbon atom adjacent to the ring. When thenumber of carbon atoms is decreased in the α-chain, the number isdeleted in order starting from position 2 and when the number of carbonatoms is increased in the α-chain, compounds are named as substitutedderivatives having respective substituents at position 1 in place ofcarboxy group (C-1). Similarly, when the number of carbon atoms isdecreased in the ω-chain, the number is deleted in order starting fromposition 20 and when the number of carbon atoms is increased in theω-chain, compounds are named as substituted derivatives herringrespective substituents at position 20. Stereochemistry of the compoundsis the same as that of above formula (A) unless otherwise specified.Thus, 15-keto-PGs compound having 10 carbon atoms in the ω-chain isnominated as 15-keto- 20-ethyl-PGs.

The above formula expresses a specific configuration which is the mosttypical one, and in this specification compounds having such aconfiguration are expressed without any specific reference to it.

In general, PGDs, PGEs and PGFs have a hydroxy group on the carbon atomat position 9 and/or 11 but in the present specification the term"15-keto-PGs" includes PGs having a group other than a hydroxyl group atposition 9 and/or 11. Such PGs are referred to as9-dehydroxy-9-substituted-PGs or 11-dehydroxy-11- substituted-PGs.

As stated above, nomenclature of the component (a) is based upon theprostanoic acid. These compounds, however, can also be named accordingto the IUPAC naming system. For example,13,14-dihydro-15-keto-16R,S-fluoro-PGE₂ is(Z)-7-{(1R,2R,3R)-3-hydroxy-2-[(4R,S)-fluoro-3-oxo-1-octyl]-5-oxocyclopentyl}-hept-5-enoicacid. 13,14-dihydro-15-keto-20-ethyl-PGE₂ is(Z)-7-{(1R,2R,3R)-3-hydroxy-2-[3-oxo-1-decyl]-5-oxocyclopentyl}-hept-5-enoicacid. 13,14-dihydro-15-keto-20-ethyl-PGF₂ α isopropyl ester is isopropyl(Z)-7-[(1R,2R,3R,5S)-3,5-dihydroxy-2-{3-oxo-1-decyl)-cyclopentyl]-hept-5-enoate.13,14-dihydro-15-keto-20-methyl-PGF₂α methyl ester is methyl(Z)-7-[(1R,2R,3R,5S)-3,5-dihydroxy-2-{3-oxo-1-nonyl}-cyclopentyl]-hept-5-enonate.

Preferred Compounds

The component (a) used in the present invention may be any derivativesof PG insofar as they are saturated or unsaturated between positions 13and 14 and have an oxo group at position 15 in place of the hydroxygroup, and may have no double bond (PG subscript 1 compounds), a doublebond between positions 5 and 6 (PG subscript 2 compounds), or two doublebonds between positions 5 and 6 as well as positions 17 and 18 (PGsubscript 3 compounds).

Typical examples of the compounds used in the present invention are15-keto-PGA₁, 15-keto-PGA₂, 15-keto-PGA₃, 15-keto-PGB₁, 15-keto-PGB₂,15-keto-PGB₃, 15-keto-PGC₁, 15-keto-PGC₂, 15-keto-PGC₃, 15-keto-PGD₁,15-keto-PGD₂, 15-keto-PGD₃, 15-keto-PGE₁, 15-keto-PGE₂, 15-keto-PGE₃,15-keto-PGF₁, 15-keto-PGF₂, 15-keto-PGF₃, 13,14-dihydro-15-keto-PGA₁,13,14-dihydro-15-keto-PGA₂, 13,14-dihydro-15-keto-PGA₃,13,14-dihydro-15-keto-PGB₁, 13,14-dihydro-15-keto-PGB₂,13,14-dihydro-15-keto-PGB₃, 13,14-dihydro-15-keto-PGC₁,13,14-dihydro-15-keto-PGC₂, 13,14-dihydro-15-keto-PGC₃,13,14-dihydro-15-keto-PGD₁, 13,14-dihydro-15-keto-PGD₂,13,14-dihydro-15-keto-PGD₃, 13,14-dihydro-15-keto-PGE₁,13,14-dihydro-15-keto-PGE₂, 13,14-dihydro-15-keto-PGE₃,13,14-dihydro-15-keto-PGF₁, 13,14-dihydro-15-keto-PGF₂,13,14-dihydro-15-keto-PGF₃, wherein PG is as defined above as well astheir substitution products or derivatives.

Examples of substitution products or derivatives includepharmaceutically or physiologically acceptable salts and esters at thecarboxy group at the alpha chain, unsaturated derivatives having adouble bond or a triple bond between positions 2 and 3 or positions 5and 6, respectively, substituted derivatives having substituent(s) oncarbon atom(s) at position 3, 5, 6, 16, 17, 19 and/or 20 and compoundshaving lower alkyl or a hydroxy (lower) alkyl group at position 9 and/or11 in place of the hydroxy group, of the above PGs.

Examples of substituents present in preferred compounds are as follows:Substituents on the carbon atom at position 3, 17 and/or 19 includelower alkyl, for example, C₁₋₄ alkyl, especially methyl and ethyl.Substituents on the carbon atom at position 16 include lower alkyl e.g.methyl, ethyl etc., hydroxy and halogen atom e.g. chlorine, fluorine,aryloxy e.g. trifluoromethylphenoxy, etc. Substituents on the carbonatom at position 17 include halogen atom e.g. chlorine, fluorine etc.Substituents on the carbon atom at position 20 include saturated andunsaturated lower alkyl e.g. C₁₋₆ alkyl, lower alkoxy e.g. C₁₋₄ alkoxyand lower alkoxy (lower) alkyl e.g. C₁₋₄ alkoxy-C₁₋₄ alkyl. Substituentson the carbon atom at position 5 include halogen atom e.g. chlorine,fluorine etc. Substituents on the carbon atom at position 6 include oxogroup forming carbonyl. Stereochemistry of PGs having hydroxy, loweralkyl or lower (hydroxy) alkyl substituent on the carbon atom atposition 9 and/or 11 may be alpha, beta or mixtures thereof.

Especially preferred compounds are those having a lower alkyl e.g.methyl, ethyl, propyl, isopropyl, butyl, hexyl, preferably C₂₋₄ alkyland most preferably ethyl at position 20.

A group of preferred compounds used in the present invention has theformula ##STR2## wherein X and Y are hydrogen, hydroxy, halo, loweralkyl, hydroxy(lower)alkyl, or oxo, with the proviso that at least oneof X and Y is a group other than hydrogen, and 5-membered ring may haveat least one double bond, A is --COOH or its pharmaceutically acceptablesalt or ester, B is --CH₂ --CH₂ --, --CH═CH-- or --C═C--, R₁ is bivalentsaturated or unsaturated, lower or medium aliphatic hydrocarbon residuewhich is unsubstituted or substituted with halo, oxo or aryl, R₂ issaturated or unsaturated, medium aliphatic hydrocarbon residue having 5or more carbon atoms in the main or straight chain moiety which isunsubstituted or substituted with halo, hydroxy, oxo, lower alkoxy,lower alkanoyloxy, cyclo(lower)alkyl, aryl or aryloxy.

In the above formula, the term "unsaturated" in the definitions for R₁and R₂ is intended to include at least one and optionally more than onedouble bond and/or triple bond isolatedly, separately or seriallypresent between carbon atoms of the main and/or side chains. Accordingto usual nomenclature, an unsaturation between two serial positions isrepresented by denoting the lower number of said two positions, and anunsaturation between two distal positions is represented by denotingboth of the positions. Preferred unsaturation is a double bond atposition 2 and a double or triple bond at position 5.

The term "lower or medium aliphatic hydrocarbon residue" or "mediumaliphatic hydrocarbon residue" refers to a straight or branched chainhydrocarbyl group having 1 to 14 carbon atoms or 5 to 14 carbon atoms,respectively, (for a side chain, 1 to 3 carbon atoms being preferred)and preferably 2 to 8 carbon atoms for R₁ and 6 to 9 carbon atoms forR₂.

The term "halo" denotes fluoro, chloro, bromo and iodo.

The term "lower" throughout the specification is intended to include agroup having 1 to 6 carbon atoms unless otherwise specified.

The term "lower alkyl" as a group or a moiety in hydroxy(lower)alkyl,monocyclic aryl(lower) alkyl, monocyclic aroyl(lower)alkyl orhalo(lower)alkyl includes saturated and straight or branched chainhydrocarbon radicals containing 1 to 6, carbon atoms, e.g. methyl,ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl and hexyl.

The term "lower alkoxy" refers to the group lower-alkyl-O- wherein loweralkyl is as defined above.

The term "hydroxy(lower)alkyl" refers to lower alkyl as defined abovewhich is substituted with at least one hydroxy group, e.g.hydroxymethyl, 1-hydroxyethyl, 2-hydroxyethyl and1-methyl-1-hydroxyethyl.

The term "lower alkanoyloxy" refers to a group of the formula: RCO-O-wherein RCO- is an acyl group formed by oxidation of a lower alkyl groupas defined above, e.g. acetyl.

The term "cyclo(lower)alkyl" refers to a cyclic group formed bycyclization of a lower alkyl group as defined above.

The term "aryl" includes unsubstituted or substituted aromaticcarbocyclic or heterocyclic (preferably monocyclic) groups, e.g. phenyl,tolyl, xylyl and thienyl. Examples of substituents are halo andhalo(lower)alkyl wherein halo and lower alkyl being as defined above.

The term "aryloxy" refers to a group of the formula: ArO- wherein Ar isaryl as defined above.

Suitable "pharmaceutically acceptable salts" includes conventionalnon-toxic salts, and may be a salt with an inorganic base, for examplean alkali metal salt (e.g. sodium salt, potassium salt, etc.) and analkaline earth metal salt (e.g. calcium salt, magnesium salt, etc.),ammonium salt, a salt with an organic base, for example, an amine salt(e.g. methylamine salt, dimethylamine salt, cyclohexylamine salt,benzylamine salt, piperidine salt, ethylenediamine salt, ethanolaminesalt, diethanolamine salt, triethanolamine salt,tris(hydroxymethylamino)ethane salt, monomethyl-monoethanolamine salt,procaine salt, caffeine salt, etc.), a basic amino acid salt (e.g.arginine salt, lysine salt, etc.), tetraalkyl ammonium salt and thelike. These salts can be prepared by the conventional process, forexample from the corresponding acid and base or by salt interchange.

Examples of the "pharmaceutically acceptable esters" are aliphaticesters, for example, lower alkyl ester e.g. methyl ester, ethyl ester,propyl ester, isopropyl ester, butyl ester, isobutyl ester, t-butylester, pentyl ester, 1-cyclopropylethyl ester, etc., lower alkenyl estere.g. vinyl ester, allyl ester, etc., lower alkynyl ester e.g. ethynylester, propynyl ester, etc., hydroxy(lower) alkyl ester e.g.hydroxyethyl ester, lower alkoxy(lower)alkyl ester e.g. methoxymethylester, 1-methoxyethyl ester, etc., and aromatic esters, for example,optionally substituted aryl ester e.g. phenyl ester, tosyl ester,t-butylphenyl ester, salicyl ester, 3,4-di-methoxyphenyl ester,benzamidophenyl ester etc., aryl(lower)alkyl ester e.g. benzyl ester,trityl ester, benzhydryl ester, etc. Examples of the amides are mono- ordi- lower alkyl amides e.g. methylamide, ethylamide, dimethylamide,etc., arylamide e.g. anilide, toluidide, and lower alkyl- oraryl-sulfonylamide e.g. methylsulfonylamide, ethylsulfonylamide,tolylsulfonylamide etc.

The term "pharmaceutically" is intended to be "ophthalmically" when usedin connection with an ophthalmic composition.

Preferred examples of A include --COOH, --COOCH₃, --COOCH₂ CH₃ and--COOCH(CH₃)₂.

The configuration of the ring and the α- and/or omega chain in the aboveformula (I) may be the same as or different from that in the primaryPGs. However, the present invention also includes a mixture of acompound having a primary configuration and that of an unprimaryconfiguration.

Examples of the typical compounds of the present invention are15-keto-20-loweralkyl-PGAs to Fs and their derivatives e.g. Δ²-derivatives, 3R,S-methyl-derivatives, 6-oxo-derivatives,5R,S-fluoro-derivatives, 5,5-difluoro-derivatives,16R,S-methyl-derivatives, 16,16-dimethyl-derivatives,16R,S-fluoro-derivatives, 16,16-difluoro-derivatives,17S-methyl-derivatives, 17R,S-fluoro-derivatives,17,17-difluoro-derivatives and 19-methyl-derivatives.

The component (a) may be in the keto-hemiacetal equilibrium by forming ahemiacetal between hydroxy group at position 11 and ketone at position15.

The proportion of both tautomeric isomers, when present, variesdepending on the structure of the rest of the molecule or kind of anysubstituent present and, sometimes, one isomer may predominantly bepresent in comparison with the other. However, in this invention, it isto be appreciated that the compounds used in the invention include bothisomers. Further, while the compounds used in the invention may berepresented by a structure or name based on keto-form regardless of thepresence or absence of the isomers, it is to be noted that suchstructure or name does not intend elimination of the hemiacetal type ofcompounds.

In the present invention, any of the individual tautomeric isomers, amixture thereof, or optical isomers, a mixture thereof, a racemicmixture, and other isomers such as steric isomers can be used in thesame purpose.

Some of the compounds used in the present invention may be prepared bythe method disclosed in Japanese Patent Publications (unexamined) No.A-108/1990 and No. A-96528/1990.

Alternatively, these compounds may be prepared by a process analogous tothat described in the above publications in combination with the knownsynthetic method for the five-membered ring moiety.

In the process for preparing 13,14-dihydro-15-keto-compound:

A commercially available (-)-Corey lactone, which is used as a startingmaterial, is subjected to Collins oxidation to give an aldehyde. Thealdehyde is allowed to react with dimethyl (2-oxoalkyl)phosphonate anionto give an α,β-unsaturated ketone, and the resultant is reduced toketone. The carbonyl group of the ketone is allowed to react with a diolto give a ketal, thereby protected, then a corresponding alcohol isobtained by elimination of the phenylbenzoyl group, and the resultinghydroxy group is protected with dihydropyran to give a tetrapyranylether. Thus, precursors of PGs wherein the ω-chain is13,14-dihydro-15-keto-alkyl can be obtained.

Using the above tetrapyranyl ether as a starting material, 6-keto-PG₁ swith the group: ##STR3## may be obtained as follows: The tetrapyranylether is reduced using diisobutyl aluminium hydride and the like to givea lactol, which is allowed to react with a ylide obtained from(4-carboxybutyl)triphenylphosphonium bromide, and the resultant issubjected to esterification followed by cyclization, combining the5,6-double bond and the C-9 hydroxyl group with NBS or iodine, providinga halide. The resultant is subjected to dehydrohalogenation with DBU andthe like to give a 6-keto compound, which is subjected to Jonesoxidation followed by deprotection to give the objective compound.

Further, PG₂ s with the group: ##STR4## may be obtained as follows: Theabove tetrapyranyl ether is reduced to the lactol, which is allowed toreact with a ylide obtained from (4-carboxybutyl)triphenylphosphoniumbromide to give a carboxylic acid. The resultant is subjected toesterification followed by Jones oxidation and deprotection to give theobjective compound.

In order to obtain PG₁ s with the group: ##STR5## using the abovetetrapyranyl ether as a starting material, in the same manner as PG₂with the group: ##STR6## the 5,6-double bond of the resulting compoundis subjected to catalytic reduction followed by deprotection. To prepare5,6-dehydro-PG₂ s containing a hydrocarbon chain of the formula:##STR7## a monoalkyl copper complex or a dialkyl copper complex of theformula: ##STR8## is subjected to 1,4-addition with4R-t-butyldimethylsilyloxy-2-cyclopenten-1-one, and the resulting copperenolate is seized with 6-carboalkoxy-1iodo-2-hexyne or a derivativethereof.

PGs containing a methyl group instead of a hydroxy group at the C-11position may be obtained as follows: PGA obtained by Jones oxidation ofthe hydroxy group at the C-9 position of the 11-tosylate is allowed toreact with a dimethyl copper complex to give 11-dehydroxy-11-methyl-PGE.Alternatively, an alcohol obtained after elimination of p-phenylbenzoylgroup is converted to a tosylate. An unsaturated lactone obtained by DBUtreatment of the tosylate is converted to a lactol. After introductionof an c-chain using Wittig reaction, the resulting alcohol (C-9position) is oxidized to give PGA. PGA is allowed to react with dimethylcopper complex to give 11-dehydroxy-11-methyl-PGE. The resultant isreduced using sodium borohydride and the like to give11-dehydroxy-11-methyl-PGF.

PGs containing a hydroxymethyl group instead of a hydroxyl group at theC-11 position is obtained as follow: 11-dehydroxy-11-hydroxymethyl-PGEis obtained by a benzophenone-sensitized photoaddition of methanol toPGA. The resultant is, for example, reduced using sodium borohydride togive 11-dehydroxy-11-hydroxymethyl-PGF.

16-Fluoro-PGs may be obtained using dimethyl(3-fluoro-2-oxoalkyl)phosphonate anion in the preparation of an α,β-unsaturated ketone. Similarly, 19-methyl-PGs may be obtained using adimethyl (6-methyl-2-oxoalkyl)phosphonate anion.

The preparations in the present invention are not construed to belimited to them, and suitable means for protection, oxidation, reductionand the like may be employed,

The carbonate dehydratase inhibitor used as the component (b) in thepresent invention refer to agents capable of inhibiting enzymes whichcatalyze the reaction forming carbon dioxide and water from carbonate(HCO₃ ⁻). Typical examples of such agents are compounds having one ormore sulfamoyl groups combined to benzene or N- and/or S-containing 5-or 6- membered heterocyclic ring which is optionaly substituted by loweralkyl, halo, lower alkanoylamide or imido, and analogues thereof.Typically these have urine secretion improving effect and areexemplified by acetazolamide, methazolamide, diclofenamide, etc.

Since the component (a) has an activity of lowering ocular pressurewithout accompanying transient ocular hypertension as shogun by theprimary PGs, the combination of (a) and (b) can be used for thetreatment of various disease and conditions in which lowering of ocularpressure is desirous, for example glaucoma, ocular hypertension andother disease which accompanies increase in ocular pressure.

As used herein, the term "treatment" or "treating" refers to any meansof control of a disease in a mammal, including preventing the disease,curing the disease, relieving the disease and arresting or relieving thedevelopment of the disease.

The combination has an advantage, by containing the component (b) inaddition to the component (a), that it has a synergistically increasedocular hypotensive action, thus enabling reduce in dosage, and/orlowering the side-effect.

The ratio (a):(b) in the combination varies, without limitation,ordinarily within the range 1:0.5 to 1:200, preferably 1:1 to 1:100 andmost preferably 1:2 to 1:50.

While the dosage of the component (a) varies depending on condition ofthe component(a) varies depending on condition of the patient, severityof the disease, purpose of the treatment, judgement of the physician andtotal dosage of the combination, it is ordinarily within the range 0.005to 2% and preferably 0.01 to 1% by weight.

The dosage of the component (b) varies, for example, depending on theconcentration of the component (a) and ordinarily within the range 0.005to 20% and preferably 0.01 to 10% by weight.

The combination according to the present invention can be administeredin the form of a pharmaceutical composition containing the components(a) and (b) and optionally other ingredients conveniently used in theophthalmic, injective or oral composition, such as carrier, diluent orexcipient.

The composition used according to the invention includes liquids such assolution, emulsion, dispersion etc. and semisolids such as ophthalmicgel, ointment etc. Diluents for the aqueous solution or suspensioninclude, for example, distilled water and physiological saline. Diluentsfor the nonaqueous solution and suspension include, for example,vegetable oils e.g. olive oil, liquid paraffin, mineral oil, andpropylene glycol and p-octyldodecanol. The composition may also containisotonization agents such as sodium chloride, boric acid, sodiumcitrate, etc. to make isotonic with the lacrimal fluid and bufferingagents such as borate buffer, phosphate buffer, etc. to maintain pHabout 5.0 to 8.0. Further, stabilizers such as sodium sulfite, propyleneglycol, etc., chelating agents such as sodium edetate, etc., thickenerssuch as glycerol, carboxymethylcellulose, carboxyvinyl polymer, etc. andpreservatives such as methyl paraben, propyl paraben, etc. may also beadded. these can be sterilized e.g. by passing through a bacterialfilter or by heating.

The ophthalmic ointment may contain vaseline, Plastibase, Macrogol, etc.as a base and surfactant for increasing hydrophilicity. It may alsocontain geling agents such as carboxymethylcellulose, methylcellulose,carboxyvinyl polymer, etc.

In addition, the composition may contain antibiotics such aschloramphenicol, penicilin, etc. in order to prevent or treat bacterialinfection.

A more complete understanding of the present invention can be obtainedby reference to the following Preparation Examples, Formulation Examplesand Test Examples which are provided herein for purpose of illustrationonly and are not intended to limit the scope of the invention.

PREPARATIONS

Preparations of 13,14-dihydro-15-keto-20-ethyl-PGA₂ isopropyl ester,13,14-dihydro-15-keto-20-ethyl-PGE₂ isopropyl ester and13,14-dihydro-15-keto-20-ethyl-PGF₂α isopropyl ester (cf Preparationchart I):

1) Preparation of1S-2-oxa-3-oxo-6R-(3-oxo-1-trans-decenyl)-7R-(4-phenylbenzoyloxy)-cis-bicyclo[3.3.0]-octane(3):

Commercially available (-)-Corey lactone (1) (7 g) was subjected toCollins oxidation in dichloromethane to give aldehyde (2). The resultantwas allowed to react with dimethyl (2-oxononyl)phosphonate (4.97 g)anion to give1S-2-oxa-3-oxo-6R-(3,3-ethylendioxy-1-trans-decenyl)-7R-(4-phenylbenzoyloxy)-cis-bicyclo[3.3.0]-octane(3).

2) Preparation cf1S-2-oxa-3-oxo-6R-(3-oxodecyl)-7R-(4-phenylbenzoyloxy)-cis-bicyclo[3.3.0]-octane(4):

Unsaturated ketone (3) (7.80 g) was reduced in ethyl acetate (170 ml)using 5% Pd/C under hydrogen atmosphere. The product obtained after theusual work-up (4) was used in the following reaction.

3) Preparation of1S-2-oxa-3-oxo-6R-(3,3-ethylenedioxy-decyl)-7R-(4-phenylbenzoyloxy)-cis-bicyclo[3.3.0]-octane(5):

Saturated ketone (4) was converted to ketal (5) in dry benzene (150 mL)using ethylene glycol and p-toluenesulfonic acid (catalytic amount).

4) Preparation of1S-2-oxa-3-oxo-6R-(3,3-ethylenedioxy-decyl)-7R-hydroxy-cis-bicyclo[3.3.0]-octane(6):

To a solution of ketal (5) in absolute methanol (150 ml) was addedpotassium carbonate (2.73 g). The mixture was stirred overnight at roomtemperature. After neutralization with acetic acid, the resultant wasconcentrated under reduced pressure. The resulting crude product wasextracted with ethyl acetate. The organic layer was washed with a diluteaqueous solution of sodium bicarbonate and a saline, and dried. Thecrude product obtained after evaporation was chromatographed to givealcohol (6). Yield; 3.31 g

5) Preparation of lactol (7):

Alcohol (6) (0.80 g) was reduced in dry toluene (8 ml) using DIBAL-H at-78 ° C. to give lactol (7).

6) Preparation of 13,14-dihydro-15,15-ethylenedioxy-20-ethyl-PGF₂ α (8):

A DMSO solution of lactol (7) was added to ylide prepared from(4-carboxybutyl)triphenylphosphonium bromide (3.65 g). The reactionmixture was stirred overnight to give carboxylic acid (8).

7) Preparation of 13,14-dihydro-15,15-ethylenedioxy-20-ethyl-PCF₂ αisopropyl ester (9):

Carboxylic acid (8) was converted to13,14-dihydro-15,15-ethylenedioxy-20-ethyl-PGF₂ α isopropyl ester (9)using DBU and isopropyl iodide in acetonitrile.

Yield; 0.71 g

8) Preparation of 13,14-dihydro-15-keto-20-ethyl-PGF₂ α isopropyl ester(10):

13,14-Dihydro-15,15-ethylenedioxy-20-ethyl-PGF₂ α isopropyl ester (9)(0.71 g) was kept in acetic acid/THF/water (3/1/1) at 40 ° C. for 3hours. The crude product obtained after concentration under reducedpressure was chromatographed to give 13,14-dihydro-15-keto-20-ethyl-PGF₂α isopropyl ester (10).

Yield; 0.554 g

9 ) Preparation of 13,14-dihydro-15-keto-20-ethyl-PGA₂ isopropyl ester(12):

A solution of 13,14-dihydro-15-keto-20-ethyl-PGF₂ α isopropyl ester (10)(0.125 g ) and p-toluenesulfonyl chloride (0.112 g) in pyridine (5 ml)was maintained at 0° C. for 2 days. According to the usual work-up,tosylate (11) was obtained.

Tosylate (11) was subjected to Jones oxidation in acetone (8 ml) at -25° C. The crude product obtained after the usual work-up waschromatographed to give 13,14-dihydro-15-keto-20-ethyl-PGA₂ α isopropylester (2).

Yield; 0.060 g

10) Preparation of13,14-dihydro-15,15ethylenedioxy-20-ethyl-11-t-butyldimethylsiloxy-PGF.sub.2α isopropyl ester (13).

13,14-Dihydro-15,15-ethylenedioxy-20-ethyl-PGF₂ α isopropyl ester (9)(3.051 g) was dissolved in dry N,N-dimethylformamide (25 ml),t-butyldimethylsilyl chloride (1.088 g) and imidazole (0.49 g) was addedthereto. The resultant was stirred at room temperature overnight. Thereaction mixture was concentrated under reduced pressure, and theresulting crude product was chromatographed to give13,14-dihydro-15,15-ethylenedioxy-20-ethyl-11-t-butyldimethylsiloxy-PGF.sub.2α isopropyl ester (13).

Yield; 2.641 g

11) Preparation of13,14-dihydro-15,15-ethylenedioxy-20-ethyl-11-t-butyldimethylsiloxy-PGE.sub.2isopropyl ester (14):

13,14-Dihydro-15,15-ethylenedioxy-20-ethyl-11-t-butyldimethylsiloxy-PGF.sub.2α isopropyl ester (13) (1.257 g) was subjected to Jones oxidation at -40° C. After the usual work-up, the resulting crude product waschromatographed to give13,14-dihydro-15,15-ethylenedioxy-20-ethyl-11-t-butyldimethylsiloxy-PGE.sub.2isopropyl ester (14).

Yield; 1.082 g

12) Preparation of 13,14-dihydro-15-keto-20-ethyl-PGE₂ isopropyl ester(15):

To a solution of13,14-dihydro-15,15-ethylenedioxy-20-ethyl-11-t-butyldimethylsiloxy-PGE.sub.2isopropyl ester (14) in acetonitrile was added hydrofluoric acid (46%aqueous solution). The mixture was stirred at room temperature for 40minutes. The crude products obtained after usual work-up waschromatographed to give 13,14-dihydro-15-keto-20-ethyl-PGE₂ isopropylester (15).

Yield; 0.063 g (97%)

¹ HNMR: δ0.86(3H,t,J=5 Hz), 2.20(6H,d,J=6.5 Hz), 1.05-2.96(29H,m),4.01(1H,m), 4.95(1H,hept,J=6.5 Hz), 5.34(2H,m). MS (EI):m/z422 (M⁺), 404(M⁺ -H₂ O), 345(M⁺ -H₂ O-i-C₃ H₂ O). ##STR9##

Formulation Example 1

    ______________________________________                                        (Ophthalmic solution)                                                         ______________________________________                                        (A)       Component (a)     50    mg                                                    Component (b)     50    mg                                          (B)       Physiological saline                                                                            10    ml                                          ______________________________________                                    

The above (A) and (B) were placed in separate vials. The vials werecombined for preparing a solution on actual use.

Formulation Example 2

    ______________________________________                                        (Injectable solution)                                                                          (parts by weight)                                            ______________________________________                                        Component (a)      0.1                                                        Component (b)      0.1                                                        Nonion surfactant  2                                                          Distilled water for injection                                                                    98                                                         ______________________________________                                    

The above ingredients were mixed and sterilized to give an injectablesolution.

Formulation Example 3

    ______________________________________                                        (Capsule)                                                                                  (parts by weight)                                                ______________________________________                                        Component (a)  0.5                                                            Component (b)  0.5                                                            Panasate*      99                                                             ______________________________________                                         *Trade Mark                                                              

The above ingredients were mixed and filled in soft gelatine capsules.

Test Example 1

Japanese white rabbits (weight: 2.0-3.0 kg, 6 animals/group) were fixedand eyes were anesthetized by dropping 0.4% oxybuprocaine hydrochlorideto eyes. The ocular pressure measured at 0.5-1 hour after the fixationwas taken as the 0 hour value and values of pressure thereafter weremeasured in the course of time administering through the auricular veina solution containing 0.2 mg/kg of each of the compounds shown in TestPlot and dissolved in distilled water for injection. An electroninpneumatonometer (Alcon) was used for measurement. Decrease in ocularpressure (mean value) at 3 hours after administration of each of thecompounds was compared in the Table 1.

                  TABLE 1                                                         ______________________________________                                                                    Decrease in                                       Test Plot                                                                            Compound  Dose (mg/kg:                                                                             ocular pressure (mmHg)                            ______________________________________                                        1      1         1.0        -0.2                                              2      2         1.0        -0.3                                              3      1         1.0        -2.9                                                     2         1.0                                                          ______________________________________                                         Compound 1: Isopropyl                                                         (Z)7-[(1R,2R,3R,5S)3,5-dihydroxy-2-(3-oxodecyl)cyclopentylhept-5-enoate       [13,14dihydro-15-keto-20-ethyl-PGF.sub.2 α isopropyl exter,             Compound 2: Acedazolamide (Acetazolamide Sodium)                         

The above results show that the combined use of acetazolamide andCompound A results in a synergistic effect.

What we claim is:
 1. A method for treatment of ocular hypertension whichcomprises ocularly administering, to a subject in need of suchtreatment, an oculo-hypotensively synergistic combination of (a) a13,14-dihydro-15-keto-20-lower alkyl prostaglandin F or apharmaceutically acceptable salt thereof or a lower alkyl ester thereofand (b) acetazolamide, or a pharmaceutically acceptable salt thereof, inan amount effective in treatment of ocular hypertension.
 2. The methodaccording to claim 1, in which the components (a) and (b) areadministered in the ratio (a):(b) of 1:1 to 1:100.
 3. The methodaccording to claim 2, in which the components (a) and (b) areadministered in the ratio (a):(b) of 1:1.
 4. A method for treatment ofocular hypertension which comprises ocularly administering, to a subjectin need of such treatment, an oculo-hypotensively synergisticcombination of (a) a 13,14-dihydro-15-keto-20-ethyl prostaglandin F or apharmaceutically acceptable salt thereof or a lower alkyl ester thereofand (b) acetazolamide, or a pharmaceutically acceptable salt thereof, inan amount effective in treatment of ocular hypertension.
 5. The methodaccording to claim 4, in which the components (a) and (b) areadministered in the ratio (a):(b) of 1:1 to 1:100.
 6. The methodaccording to claim 5, in which the components (a) and (b) areadministered in the ratio (a):(b) of 1:1.
 7. A method for treatment ofocular hypertension which comprises ocularly administering, to a subjectin need of such treatment, an oculo-hypotensively synergisticcombination of (a) a 13,14-dihydro-15-keto-20-ethyl prostaglandin F₂α ora pharmaceutically acceptable salt thereof or a lower alkyl esterthereof and (b) acetazolamide, or a pharmaceutically acceptable saltthereof, in an amount effective in treatment of ocular hypertension. 8.The method according to claim 7, in which the components (a) and (b) areadministered in the ratio (a):(b) of 1:1 to 1:
 100. 9. The methodaccording to claim 8, in which the components (a) and (b) areadministered in the ratio (a):(b) of 1:1.